I have a external nodejs library (being consumed in my nodejs app) with the following implementation,

export type Client = InstanceType<Issuer['Client']>;
declare class BaseClient {
  constructor(metadata: ClientMetadata);
  metadata: ClientMetadata;
  issuer: Issuer<this>;
  static issuer: Issuer<BaseClient>;

  authorizationUrl(parameters?: AuthorizationParameters): string;
  callbackParams(input: string): CallbackParamsType;
}

export class Issuer<TClient extends BaseClient = BaseClient> {
  constructor(metadata: IssuerMetadata);

  Client: TypeOfGenericClient<TClient>;

  metadata: IssuerMetadata;
  static discover(issuer: string): Promise<Issuer<BaseClient>>;
}

export interface TypeOfGenericClient<TClient extends BaseClient = BaseClient> {
  new (metadata: ClientMetadata): TClient;
}

The result of authorizationUrl is being used in my my public method.

public async getUrlMethod(): Promise<string> {
  const client = await this.client.get(); // setup BaseClient instance
  const result = client.callbackParams('callbackUrl');

  //use the result and return back string.
}

How can I unit test the getUrlMethod method by mocking off callbackParams using Jest?

Referred to text text, But in my case I am working with wrappers and mocking is doesn’t look straightforward.